Biogenic Silver Nanoparticles Decorated with Methylene Blue Potentiated the Photodynamic Inactivation of Pseudomonas aeruginosa and Staphylococcus aureus

Abstract

The persistence of multidrug resistance among microorganisms has directed a mandate towards a hunt for the development of alternative therapeutic modalities. In this context, antimicrobial photodynamic therapy (aPDT) is sprouted as a novel strategy to mitigate biofilms and planktonic cells of pathogens. Nanoparticles (NPs) are reported with unique intrinsic and antimicrobial properties. Therefore, silver NPs (AgNPs) were investigated in this study to determine their ability to potentiate the aPDT of photosensitizer against Staphylococcus aureus and Pseudomonas aeruginosa. Biologically synthesized AgNPs were surface coated with methylene blue (MB) and studied for their aPDT against planktonic cells and biofilms of bacteria. The nano-conjugates (MB-AgNPs) were characterized for their size, shape and coated materials. MB-AgNPs showed significant phototoxicity against both forms of test bacteria and no toxicity was observed in the dark. Moreover, activity of MB-AgNPs was comparatively higher than that of the free MB, which concludes that MB-AgNPs could be an excellent alternative to combat antibiotic resistant bacteria.

Design of Photosensitizing Agents for Targeted Antimicrobial Photodynamic Therapy

“…The 1 O 2 * generated by RB upon white light irradiation combines with Ag + ions release to kill S. mutans in a more efficient way than either alone, while the antibacterial activity of the clusters was reported to be maintained even after irradiation thanks to the released ions ( Figure 12 ,b). Other AgNPs-MB electrostatic conjugates reported by Parasuraman et al inactivated P. aeruginosa and S. aureus with enhanced efficiency compared to MB alone, and without significant dark activity [ 161 ]. Interestingly, the AgNPs were prepared by bacteria-mediated synthesis, and the biogenic AgNPs enhanced the uptake of MB by pathogenic strains.…”

A Review on Silver Nanoparticles: Classification, Various Methods of Synthesis, and Their Potential Roles in Biomedical Applications and Water Treatment

“…Scientists worldwide are trying to develop new drugs using nanotechnology to decrease antibiotic resistance [171]. Nanotechnology has produced new aspects to treat infections via minute-scale resources and overcome the side effects of available drugs by using green methods [172]. The AgNPs are identified for their excessive antimicrobial/bactericidal activities, and this inhibitory effect can be used to remedy contagious illnesses better [173].…”

Enhanced Antibacterial and Anti-Biofilm Activities of Antimicrobial Peptides Modified Silver Nanoparticles

“…With the rapid development of nanotechnology, a lot of novel antimicrobial agents and methods have been put forward and studied, such as antibacterial peptides (AMP), 27 , 28 quaternary ammonium compounds, 29 quantum dots, 30 photodynamic therapy 31 and photothermal therapy. 32 Antimicrobial peptides are a diverse group of naturally occurring molecules, which can be produced by various kinds of living organisms including bacteria and animals. 33 They are increasingly being considered as useful alternatives to conventional antibiotics because of their potent membrane-targeting.…”